title: Neuroprotective effects of ischemic postconditioning on global brain ischemia in rats through upregulation of hippocampal glutamine synthetase.
abstract: Brain ischemic postconditioning is the induction of brief periods of ischemia-reperfusion during the early stages following ischemia, and it has been shown to produce neuroprotective effects. The mechanisms underlying these neuroprotective effects are poorly understood. Glutamate excitotoxicity is one cause of postischemic neuronal death. Glutamine synthetase (GS) is an enzyme that is expressed in glial cells and may affect glutamate excitotoxicity. We induced global ischemia in rats and performed postconditioning with 6 cycles of 10 seconds reperfusion and 10 seconds reocclusion before final reperfusion. Hematoxylin and eosin staining revealed extensive neuronal loss (44.0 ± 2.8% cell survival) in the hippocampal CA1 region. Ischemic postconditioning decreased neuronal death (82.0 ± 5.6% cell survival; p<0.05). Western blotting revealed significantly increased GS expression in the hippocampus for the ischemia-reperfusion group over time compared with the sham group (p<0.05). Ischemic postconditioning resulted in significantly increased (p<0.05) GS expression compared with both the sham and ischemia-reperfusion groups, suggesting that upregulation of GS expression after ischemia constitutes a neuroprotective mechanism.
authors.affiliation: Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, 1630 Dong Fang Road, Pudong New District, Shanghai 200127, China.
authors.forename: Weiqiao
authors.initials: W
authors.lastname: Zhang
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Miao
authors.forename: Sanquan
authors.initials: S
authors.lastname: Zhou
authors.forename: Jiyao
authors.initials: J
authors.lastname: Jiang
authors.forename: Qizhong
authors.initials: Q
authors.lastname: Luo
authors.forename: Yongming
authors.initials: Y
authors.lastname: Qiu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000503:physiopathology; D057775:Ischemic Postconditioning; D008297:Male; D009474:Neurons / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation
chemical_list: D005974:Glutamate-Ammonia Ligase